The invention relates to a method for optimising a property of a satellite system. The invention further relates to an optimisation device for at least one property of a satellite system, a satellite receiver, a satellite system, a satellite tracking system and a computer program product.
In the art satellite systems are known comprising a transmitter in a satellite which can transmit a satellite signal and a satellite receiver which can receive a satellite signal. Usually, the satellite receiver is an antenna system on the ground at a distance from the satellite. Often, the satellite broadcasts television signals and the satellite receiver is used to receive the television signals, however other data can also be received and transmitted. In the art satellite system are known in which the satellite receiver has one single dish or lens shaped antenna. A dish or lens shaped antenna has a fixed antenna beam width which is usually 3 degrees or less to assure receiving signals from just one satellite at a time. The fixed antenna beam width assures an optimal pointing of the dish or lens shaped antenna towards the satellite after positioning. The positioning of the dish or lens shaped antenna is performed by mechanically pointing the antenna beam towards the transmitter. This mechanical positioning is usually performed by positioning the dish shaped antenna in the predetermined position, e.g. with the antenna beam pointing in a predetermined direction in the sky.
A disadvantage of a satellite receiver provided with one single dish or lens shaped antenna is that the properties of the satellite receiver, such as the direction, polarisation, or width of the antenna beam, are either fixed or difficult to adjust. This is particularly disadvantageous when for example signals from another transmitter have to be received or the relative position of the transmitter or the satellite receiver with respect to each other change, for instance when the satellite receiver is mounted on a car, boat or other moving object or when the satellite is not in a geostationary orbit.
In the art also satellite systems are known in which the satellite receiver comprises a so called beam forming antenna array with two or more antenna elements instead of a single dish shaped antenna. Properties of the antenna array or other parts of the satellite system, such as the beam width and beam direction, can be adjusted electronically. However, to optimise or adjust one of more properties or the satellite system, additional methods and devices are required to adjust or optimise one or more aspects of the satellite system.
From the United States patent publication 5 929 804, a method and system for optimising reconfiguration of a reconfigurable zonal beam forming system for an antenna on a satellite in orbit is known. The method and system optimise the phase changes of phase shifters and attenuation of attenuators in the reconfigurable zonal beam forming system. In the optimisation, an error function is defined and using Butler matrixes desired values of the phase shifts and attenuators are determined.
However, a disadvantage of the prior art known from this patent publication is that it requires a large amount of processing power, because of the matrix manipulation involved.